After reading my conundrum with my astrophotography equipment, I gathered what I had and looked for a solution.
Since I’m in no way able to afford a huge tricked out scope (we got a great deal on my 8″ LX10 on craigslist!) I’m sticking with what I have. Again, there’s a tracker on my scope but it is basically a barn door tracker. It is slightly more sophisticated though, it has a controller with “North, South, East, and West” buttons on it. As long as it is perfectly polar aligned (I’ll talk about this later) all I have to do is turn it on and it’ll automatically track whatever the scope is pointed at (this is typical barn door behavior) but if I want to drive the scope to look at something to the east, I hold down the “East” button on the controller, and it will DOUBLE the speed of the motor… making 1 revolution in 12 hours instead of 24. Wow right! Not so speedy. Well, it gets better. If I want to look at something West of my current object, holding the “West” button turns the motor off completely. The telescope then simply waits for the earth to spin until that object is within view. The North and South buttons work a little differently, the scope doesn’t move either of these directions unless a button is pushed. When it is, it turns on a motor that moves **Just as slow as the tracker motor.** It can also only move in a particular North/South direction until a screw on the mount bottoms out. This limits the number of degrees of rotation I can do North to South. Typically, I set it up so that when I start viewing, I’m in the middle of the screw, which gives me just as much leeway North as South, but halves the total amount I can move the scope in any one particular direction.
All this means that there’s no way I can whip this thing around to look at whatever I want automatically like GoTo systems do. I’ll have to unlock the clutches on each axis, then swing it manually to point at an object of interest, then lock the clutches down again and let the motors take over. I’m fine with that, but how do I know where things are in the sky? I’m not great at memorizing locations of stars and DSOs. My solution is to use a PushTo setup. A PushTo is for dumb telescopes. Basically, you attach it to your scope and it tracks where you are manually moving it to point. The best solution I’ve found for this is an app called Skeye. It is like google sky map, except it was designed so you can mount your tablet or phone to your OTA (Optical Tube Assembly… or Tube where your mirrors and lenses are). I’ll do a tutorial on how to setup and use this as well. For now, check out this guy’s setup.
So I can find objects in the sky, how do I take good photos of them? Due to budget (none really) I have to work with what I have, I first need to make sure that:
1. I am relatively well alighed with true North. (Not perfectly aligned, but close enough and I can do this quick and dirty).
2. I manually move the scope to point at what I want to look at. (This is easy enough).
3. Use a computer to automatically control the direction of the scope for long periods of time.
That last one is a doosey. And so that’s where my adventure began a few years back. I joined the yahoo support group for LX10 owners. Luckily, some of those guys have figured out different ways to hack together store-bought systems with their LX10s. Many of them were a bit too advanced for me (I don’t own a machine shop nor and I spending several hundred dollars on buying another telescope brand’s trackers and rigging it to my system in the hopes that I don’t fry it…) A guy named gt_keys had already been looking at a simple solution to connect an LX10 to computer-based guidance systems via an arduino connection. I like this idea because it can be used with multiple kinds of computer software.
The arduino hardware and code was developed by yahoo user gt_keys in Spring 2013. You can find his threads on the LX10 yahoo group; specifically, these files come from the files section. I’ll ask if he would put it on GitHub, or if he minds if I do so you can download it.
He has also developed a RaspberryPi version as well that seems to be more capable. Seeing as how the LX-10 is limited in the Dec and Right Ascension speeds, this arduino implementation will work fine for most things though you need to be connected to a computer of some type.
This requires a number of software packages to be installed:
So the hardware flow looks like this: You’ll have a USB webcam attached to your sighting scope which will feed data to a program called PHD Guider 2. See my post for how to attach a USB camera to your sighting scope. This must also have the ASCOM drivers installed which know how to talk to different telescope systems. Specifically we will need the “Meade Classic and Autostar 1” driver. (I can’t remember exactly which driver it is on the ASCOM site, but it is either this one or this one). This can be found in the settings menu of PHD2. I went through the “new equipment wizard” in PHD2 to create a group of settings for my equipment. Again, since the LX-10’s hardware is so limited, there isn’t much to enter really. There is no focus knob (though if you add one, gt_key’s arduino code seems to be able to handle it).
PHD2 will take the image from the webcam attached to your site scope and allow you to specify a particular star in the field. Once you begin tracking, PHD2 looks at how many pixels the star in your image has moved, then send the appropriate commands to move to the ASCOM drivers. These translate that command into whatever command your scope hardware requires. For instance, you might have an autoguiding Orion scope. There’s drivers for all of that stuff. In our case, the Meade LX10 doesn’t have a computer language, so gt_keys chose to use the classic Meade and Autostar 1 command set.
The ASCOM drivers send the message over your USB serial port to the arduino. gt_keys’s code reads in those commands and basically pushes the buttons on the LX-10’s hand controller electrically. The motors on the LX10 move very slow. It is literally a barn door contraption, moving a full 360 degrees in 24 hours, and if you want to drive the telescope the other direction, it just turns the motor off and waits for the earth to spin to the point you want to move to. This means that for you to get good long exposures or to track planets well enough, you have to get a relatively close polar alignment on your scope before you start. More on this in another post.
Firstly, build the schematic as shown. I used a green relay board from Seeed studios.
Secondly, before you flash the firmware to the arduino, you have to change a value to make the hand-held controller to work. This is on line 56. You must change “const int hcontrol = 0;” to “const int hcontrol = 1;” Otherwise you cannot test this thing unless you have it all connected up to the computer, getting ASCOM commands which are generated from the PHD2 program.
Other software and options:
How to guide mount PHD:
As an alternative to PHD Guider 2, (PHD2) you can try AstroTortilla. Though I’ve never tried it, here’s a tutorial for how to use it.
I have not tried these out, however I’ve seen them recommended several times. Comment and let me know if you love or hate any of these:
AstroImageJ is ImageJ for astronomy. ImageJ is a image processing program for scientific use that’s open sourced, Java-based and encourages lots of plugins, extensions, and macros to be built.
Astronomy.net can help calibrate your images through a web app. Really awesome to see other peoples’ shots as well. You can also have it pick out and name stars in images you upload. It is really cool. There’s a bot on reddit’s astro subreddits that automatically does this and posts the results if you submit images to that reddit. Here’s the bot’s feed and here’s an “Ask Me anything” AMA with the author. Oh, and the source code is completely open course too so you can hack on it if you want.
This is a quick list of Equipment I have and what I want. I have yet to have the time to get any spectacular images yet, but I think I could get some good ones given some practice. This is mainly a list for myself, but in case anyone else is interested in what to get for starting out in astrophotography, here’s a reference point. My next post on this topic will likely be a description of how I plan to use this to take wicked pics of planets, nebulae, and hopefully some galaxies.
My next purchases:
You can find them for as high as $600 for a hard-shell case or for a soft-shell case, about $300. We’ve had a set of luggage my mother gave us like 10 years ago and I repurposed the largest one to carry my OTA (telescope tube). It’s dimensions were perfect. 13″deep x 18″wide x 28″ tall. I went to a craft store and got some 1.5″ foam, wrapped it in a circle and smushed it into the bag. Then I cut off the excess which left me with enough to do a top and bottom and a sliver to set on the face of the tube after I lay it in there.
I did have to carefully cut a slot and hole in the top piece of foam to make a pathway for the focuser knob on the scope. This is the only thing I really worry about with this setup.
To make it look nicer and more finished, I got about 3 yards of shiny-satiny black soft fabric that I thought would be good to use and stuffed it along all the edges of the foam. I made sure to form the fabric into the slot and hole for the focuser knob. I don’t want that snagging or to have any weight on it at all. There’s no sewing involved, simply tuck in about 1 foot of material around every edge, leaving a long extra piece hanging out the bottom.
Once the tube is set in place, bring this excess fabric up, fold in the sliver of left-over foam and set it on top of the OTA. Then zip up and you are ready to go. The bag has plenty of storage for accessories, although I do not keep my lenses in this bag.
I would like to get a hard-shell case for it, but with the types of luggage available, the hard shell is very thin and I worry that it won’t hold up over time, but something like this looks a little more beefy. I’ve been looking at Ross and TJ Maxx when I happen to go to those stores, but nothing there seems to be big enough.
My current solution for a dew shield is very low tech. I got a dollar store version of this metallic accordion-style foam insulated car window reflector. because it accordions down to a small size and fits perfectly in my telescope’s bag. I attach it to my scope with a single 7″ diameter elastic headband. It works great!
I’ve been interested in astonomy my whole life, and a few years back, I got a second-hand Meade LX-10 telescope. This is a 8″ diameter scope… definitely not a toy. It is great for planetary viewing and can even track the planets as the Earth turns. I have used it from time to time to try to take some pictures of celestial objects, but not very good ones. Astrophotography is a growing interest of mine now and I found the learning curve quite steep. I’m throwing together everything I’ve learned over the past couple of years including links to software and such into a few posts. There are multiple steps involved in this project and it took me a long time, working here and there and amongst about 1000 other projects, to finally get everything together for this.
To take amazing amateur astrophotography images you need to decide whether you want to look at deep space objects (DSO) like galaxies or nebulae, or if you want to focus on planetary viewing (within our own solar system). You don’t really want to zoom very much if you want DSO images because zooming narrows your field of view and most DSOs you want to get are very dim so you don’t want to zoom in to make their light spread out across your eye or camera sensor too much, you want bright pictures. You can take some amazingly cool pictures with just a DSLR and a “barn door” tracker. (This is just a device that rotates counter to the Earth’s rotation so your camera will continue pointing at the same object for minutes or hours at a time, meaning it moves a full 360 degrees in 24 hours).
In my case, I want to do a little of both planetary and DSO. So I have my LX-10 telescope, which has an 8″ diameter mirror, meaning it can collect a lot of light, and it has a tracker so I can point a camera at one point in the sky as long as I want. However, unless you perfectly align the scope with true celestial north, the scope will still drift a bit over the night. This is because it is an open control system. You just point it at a star, turn it on and hope you aligned it well when you started. The best images are taken with closed-loop control systems. That is, they continuously look to see if it is drifting off target, then takes actions to move back on target when needed. This guy has my telescope and has taken some amazing pictures of planets, sunspots, and DSOs. Some are mindlbowingly good! To be fair, he’s using some reducer lenses like this one to change his F-stop to make it much quicker (for example F/3.75 and F/4.6 in some images), oh and he’s using a 4x Powermate lens a lot which costs as much as I spent on my entire telescope… But what is great about his site is that he tells all the settings he used for the images. This is similar to Reddit’s astrophotography subreddit.
My scope is what they call “slow,” “long,” or “dark.” This refers to the F-stop number. This is also called the focal ratio or relative aperture. It is a ratio of the len’s focal length and the diameter of the scope. THe focal length of my telescope is 2000mm. And the aperture is 8″ or 203mm. The F-stop of this would be about 2000mm / 200mm = 10. So this means my scope is a F/10 lens. The higher the f-stop number is, the darker the image will be (all other things being equal) when compared to a lens with a smaller f-stop number. For example an F/4 is considered a pretty “fast” telescope. My F/10 number basically means that to take a nice bright picture of Jupiter for instance, I need to play with the “sensitivity” or ISO number of the camera sensor (used to be film) as well as the duration I leave the shutter open on the camera.
You might say, “Well I can just crank up the sensitivity then. Higher sensitivity will make the image come out brighter, right?” The answer is yes and no. You can raise the sensitivity, but then a lot of other things (such as heat) can trigger a pixel to register a value in a digital camera. This will increase the noise in the image, making it staticy.
You might then think “Ok, the other option is to just open the shutter for a long time, exposing the camera sensor to more light over a longer time period.” yeah… not really. This can work as well, however you will increase the overall light pollution in your images and worse, you risk blurring the image. Since the Earth keeps on spinning, objects in a fixed telescope’s field of view move. Without tracking perfectly, long exposures will be blurred.
Even if you can fix all that, there’s blurring you simply cannot fix. This is due to heat inversion in the air column between you and the object you are viewing. The Hubble space telescope was designed to fix this problem… by simply being above all the air on earth orbiting in a pretty high orbital plane (at the farthest reach that the space shuttles could fly). Air at different temperatures has different densities. This acts like a prism to bend the shape of a beam of light. Look at a straw or pencil in a glass of water. Notice how it looks like it’s broken in half at the interface of the water and the air? That’s an example of the different densities acting like a prism. Since air is, well, air… it is gaseous and mixes and moves around a lot. It is in constant motion (unlike the water in your glass compared to the air sitting on top of it.) Hot air rises and cool air falls, making all sorts of weird prism effects in our viewfinder. In the column of air between you and the top of the atmosphere where Hubble is, there’s also a lot of dust. The dust as well as the temperature inversions is what makes starts look like they are twinkling.
Side note: Planets don’t twinkle in the sky when viewed by eye. This is because a star is so far away, you are only seeing it as a point light. This makes it easy for dust or temperature inversion to affect your view of it. But planets are much closer, and their light is spread slightly wider across the retina in your eye. This means there much less of a chance that a mote of dust will block it, or temperature inversion will guide the light too far from your retina.
So how do you fix the problem of having a dark image from the telescope without getting errors from too high of a sensitivity setting or blurring from too long an exposure and temperature inversions? You can thank Woz for the home computer! Using a laptop, I’m going to connect a closed-loop control system to my computer to track the objects I want to image very closely, reducing blur of long exposure images. I’m also going to take multiple images of the same object, then do a process called “stacking” where a computer algorithm will take the sharpest views of different parts of the planet, for instance, and stitch them together into a composite image that is overall much sharper. Then I’ll be able to do some image processing on the composite image to get some great results. Stay tuned for more posts on this theme!
Currently, NASA allows or direct donations however, as you can see in the next link, it is complicated to figure out to whom make the check out and mail to.
I think we should campaign to get NASA listed on a great site called Pay.gov. Pay.gov allows everyday people to donate directly to United States government agencies. One example is to help pay down the national debt. <via NPR>
By making it easier for citizens to donate to NASA, we won’t raise enough funds for a mission to Mars, but even if a conservative estimate of 1% of working Americans (134.8 million people according to wolfram alpha) donate just 10 each, we would have we would have 134,800,000 * 1% * $10 = $13.48 million dollars. That’s not a lot compared to the cost of a space mission, but it is a small help to a struggling agency that should be the jewel in the crown of America. NASA has generated a good return for investment in the past and there is no question that investment in science and technology helps strengthen our nation’s economy and morale which is needed in this time of economic uncertainty.
Moreover, an investment in NASA is an investment in the future of our nation in terms of future engineers and scientists. NASA has achieved some of the greatest feats ever accomplished in the history of mankind. Landing men on the moon, as well as increasing our understanding of our place in the universe with missions like the Mars rovers, a multitude of space telescopes, and planetary probes have all served as inspiration for people who strive to be the best the world has to offer. They are inspired to pursue man’s long passion for exploration and curiosity.
NASA has helped develop technologies that improve and even save lives every day such as MRI machines, and many other fantastic technologies. This neat site lists a new innovation from NASA every time you refresh the page. NASA has a positive impact on the world as a whole. It should be funded as such.
Lets get NASA listed on Pay.gov, not because it is easy, but because it is worth the effort! The way to do it is to get this post seen by someone who knows someone in charge at NASA who can suggest it to them.
So what is a transit anyway? A transit is when an object like an interior planet (one closer to the sun than the Earth) crosses in front of the sun that is visible to the Earth. This is one of the ways we can spot planets around other stars too. If we can watch the star long enough, we might see a dip in the star’s intensity, which might mean a planet got between us and that star. In fact, by looking at the different wavelengths of light we receive during one of these dips of intensity, we can determine the components of the atmosphere of that planet! Science is amazing right!?
Anyway, back to the phenomena at hand; the transit of Venus…
I’ve recently gotten into astronomy and astrophotography since I got an 8″ telescope for my birthday in 2010. Since then I have found that my Android phone is a must have tool! This is a list my favorite and most useful Android apps for astronomy. All of the ones mentioned here are free or have a free version. I suggest donating or upgrading on all of them if you like them to help compensate the programmers for their hard work.
UPDATED with new app (see end of post for the new addition).